1. Field of the Invention
This invention is concerned with certain phenoxybenzoic acid esters and their use as herbicides.
2. Description of the Prior Art
In U.S. Pat. No. 3,652,645, there is disclosed alkyl (C.sub.1 -C.sub.3) esters of 2-nitro-5-(halophenoxy) benzoic acids as herbicides. Under some early-season weather conditions, especially when treated soil is splashed onto the lower leaves, contact injury may be seen. On soybeans, this may appear as crinkling of the lower leaves of young plants. On corn, the effect may be a discolored band on the lower blades. Occasionally, stunting may be observed. Crop injury under high soil moisture levels may not appear for 2 or 3 weeks and is temporary. The crop will grow out of it and yields are not adversely affected.
The transverse (chlorotic) band on corn blades presents a phytotoxic appearance that is evident on the plant throughout the early growing season. Such appearance, although not adversely affecting yield, can be offensive to many growers and could dissuade them from suing an otherwise effective herbicide. It is the discovery of this invention that the alkyl (C.sub.4 -C.sub.12) and cycloalkyl (C.sub.3 -C.sub.8) esters, as well as the unsaturated hydrocarbyl (C.sub.3 -C.sub.10) esters, do not appear to give the phytotoxic appearance evidenced by the alkyl esters disclosed in U.S. Pat. No. 3,652,645.